S57 New Synthetic Pyrazine Carboxamide Derivatives as Potential Elicitors in Production of Secondary Metabolite in In vitro Cultures

Background: Silymarin, an active polyphenolic fraction of Silybum marianum, and high flavonoid content of Fagopyrum possess various interesting biological activities. The substituted pyrazine‑2‑carboxamides were previously used as effective elicitors of studied secondary metabolites. Objective: To study the effect of new synthetic pyrazine carboxamide derivatives, N‑(4‑chlorobenzyl)‑5‑tert‑butylpyrazine‑2‑carboxamide (1) and 3‑(3‑((trifluoromethyl) benzyl) amino) pyrazine‑2‑carboxamide (2), on flavonolignan and flavonoid production in S. marianum and Fagopyrumes culentum in vitro cultures. Materials and Methods: Callus and suspension cultures were cultured on MS medium containing α‑naphtaleneacetic acid or 2,4‑D. Three elicitor concentrations for different exposure times were tested. Dried and powdered samples of callus and suspension cultures were extracted with methanol and analyzed by DAD‑HPLC. Results: Compound 1 showed as a good elicitor of taxifolin production. The effect on silymarin complex was less visible with a maximum between 24 and 48 h after 3.292 × 10−4 mol/L concentration. The detailed analysis showed that silychristin was the most abundant. Compound 2 was effective in rutin production only in callus culture with maximum 24 h and 168 h after application of 3.3756 × 10−3 mol/L concentration and 48 and 72 h after 3.3756 × 10−4 mol/L concentration. Conclusion: From the results of the performed experiments, it can be concluded that compound 1 shows to be suitable elicitor for enhanced production of taxifolin and silychristin in S. marianum, mainly when 3.292 × 10−4 mol/L concentration was used, and compound 2 is suitable for increase rutin production in callus cultures and less appropriate for suspension cultures of F. esculentum.